1. Field of the Invention
The present invention relates to an inspection illuminator used, for example, upon inspecting the external appearance or scratch marks of products, which are inspection articles, by irradiating light thereto in the likes of a factory, as well as upon inspecting the soldering quality of electronic components that are mounted on a substrate.
2. Description of the Related Art
As an example of such inspection illuminator, there is Japanese Laid-Open Patent Application No. H10(1998)-21717 proposed previously by the applicant of this application. This disclosure disposes a transparent body for diffusing light on the front part of the inner peripheral side of a multiplicity of illuminants (light emitting diodes) aligned circularly in a state where the light emitting face is directed toward the inner peripheral side, and light is thereby applied on the inspection article from a circular exit face of the transparent body.
Nevertheless, with the aforementioned illuminator, since the illuminants are aligned in a single row, light can only be emitted in a fixed direction and only to the same place on the inspection article. Thus, depending on the shape or the like of an inspection article having a three-dimensional shape, there is an inconvenience in that defects cannot be discovered on the inspection face of the inspection article with irradiation from the aforementioned fixed direction.
In view of the foregoing circumstances, an object of the present invention is to overcome such problem by providing an inspection illuminator capable of reliably detecting whether there are defects on the inspection face of inspection articles.
In order to achieve the foregoing object, with the inspection illuminator of the present invention, a plurality of rows of illuminant rows are provided in which a multiplicity of illuminants are circularly aligned so as to encircle an opening formed approximately in the center; a plurality of annular transparent bodies for dispersing light from the illuminants of the illuminant rows and guiding such light toward the central axis side of the opening are layered at the front part of such illuminant rows in a state of being optically shielded with a shielding means; and the light emitting faces of the transparent bodies are formed into an incline plane, such that the upper part thereof is closer to the central axis.
Therefore, light from the respective illuminant rows moves inside the respective transparent bodies, while reflecting and scattering in a complex manner, without entering the other illuminant row sides, and irradiates the inspection article from an upward position from the exit face (inclined plane) of the terminal end of the respective transparent bodies. Further, since it is possible to make the light from the respective illuminant rows in an optically shielded state, light may be applied to an inspection article from a plurality of illuminant rows at differing angles, and it is also possible to reliably inspect the inspection face by differing the light irradiation position against the inspection article. Moreover, the inspection article to which light is applied may be visually observed through an opening, or inspection of the inspection face may be conducted through imaging with an imaging means.
Light from the respective illuminant rows may be shielded in the vertical direction by juxtaposing a plurality of rows of circularly aligned illuminant rows in the vertical direction in a state where the light emitting face of the respective illuminants are directed toward the inner peripheral face side; and disposing the plurality of transparent bodies in front of such plurality of rows of illuminant rows.
By juxtaposing a plurality of rows of illuminant rows in the vertical direction as described above, the number of illuminants of all illuminant rows to be mounted can be made the same, and it is thereby possible to avoid variations in the light volume to be applied from the respective illuminant rows.
Light of the respective illuminant groups divided into groups may be shielded in the horizontal direction by juxtaposing a plurality of rows of circularly aligned illuminant rows in the vertical direction in a state where the light emitting face of the respective illuminants are directed toward the inner peripheral face side; dividing the multiplicity of illuminants into a plurality of groups in the peripheral direction; and disposing a plurality of annular transparent bodies for guiding light from the illuminant groups divided into groups in the horizontal direction in front of the illuminant groups in a state of being optically shielded.
By juxtaposing a plurality of rows of illuminant rows in the vertical direction as described above, the number of illuminants of all illuminant rows to be mounted can be made the same, and it is thereby possible to avoid variations in the light volume to be applied from the respective illuminant rows.
Light from the respective illuminant rows may be shielded in the horizontal direction by juxtaposing a plurality of rows of circularly aligned illuminant rows in the horizontal direction in a state where the light emitting face of the respective illuminants are directed downward; and disposing the plurality of transparent bodies below such plurality of rows of illuminant rows, respectively.
According to the foregoing structure, light to be emitted from the respective illuminant rows may be efficiently emitted from the exit faces of the transparent bodies disposed below the respective illuminant rows. For example, FIG. 1 through FIG. 3(a), (b) illustrate the plurality of rows of circularly aligned illuminant rows in a state where the light emitting faces of the respective illuminants are directed toward the inner peripheral face side and, here, it is clear from the drawings that the area of the exit faces 6A of the transparent bodies 6 in comparison to the area to which the illuminants 4 are disposed is narrow due to the diameter becoming smaller, particularly that the area of the exit faces 6A positioned upward become narrower, as well as that the distance from the illuminant 4 to the exit face 6A becomes longer for those illuminants 4 positioned upward. In such a state, even if the number of the respective illuminant rows is the same, the volume of light capable of arriving at the exit face 6A from the illuminant 4 will decrease relative to the illuminants 4 positioned upward. Contrarily, as depicted in FIG. 11 and FIG. 12, the area of the exit faces 6A of the transparent bodies 6 in comparison to the area to which the illuminants 4 of the respective illuminant rows are disposed can be made approximately the same by juxtaposing a plurality of rows of circularly aligned illuminant rows in the horizontal direction in a state where the light emitting faces of the respective illuminants are directed downward; and disposing the plurality of transparent bodies below such plurality of rows of illuminant rows, respectively. Thus, it is possible to efficiently transmit light with the transparent bodies and to inhibit the reduction of light volume in comparison to those illustrated in FIG. 1 through FIG. 3(a), (b). In addition, there is another advantage in that the reduction rate of the light volume in any illuminant row may be made approximately even.
The assembly procedure of the illuminator can be conducted quickly by mounting a multiplicity of illuminants on a single substrate so as to structure the plurality of rows of the illuminant rows.
The brightness of light may be made approximately equal and it is also possible to irradiate inspection articles from different angles by forming the inclined plane of the transparent bodies in a gentle curvature face.
The brightness of light may be further made approximately equal as a result of alleviating the directivity of light upon immediately refracting and dispersing the light from the illuminants in a complex manner, by filling the gaps produced between the illuminants and the transparent bodies with filling material such as transparent silicone.
The attenuation caused by the absorption of light can be minimized by forming the shielding means of a reflective layer so as to return the light applied to such shielding means back into the transparent bodies.
A specific illuminant row or a specific illuminant group may be turned on to conduct the inspection of an inspection article by structuring the respective illuminants juxtaposed in the vertical direction or the respective illuminant groups divided into groups in the horizontal direction so as to be capable of being individually turned on and turned off.
Synthetic light in which a plurality of colors are synthesized or differing single-color light through sequential switching can be applied to the inspection article for inspection by differing the color of the respective illuminants juxtaposed in the vertical direction or the respective illuminant groups divided into groups in the horizontal direction by rows or by groups.
The irradiation volume of light of the respective illuminant rows to be applied to the inspection articles may be made to be the same or different by providing an adjustment means for adjusting the irradiation of the light volume to be emitted through the transparent bodies from the respective illuminants juxtaposed in the vertical direction.